In simple words, yes. You could most definitely fit a crib mattress to a toddler bed, unless you have an unusually small crib. Most infant beds have the same dimensions as the conventional mattress for cribs. Crib mattresses have standard dimensions 28″ x 52” which is the same as Toddler Bed mattress. So the mattress of your baby’s crib should fit in principle to your kid’s bed. Some people prefer to use the crib mattress for toddler beds since it can save money and prevent unnecessary wastage. However, you have to keep in mind toddler and newborns have different mattress requirements. Newborns should sleep on firmer mattresses, if not they might suffocate when their face gets buried in the softer surface of the mattress. Toddler bed is comparatively softer. Another thing to remember is, what kind of toddler bed you are buying. If you are not buying a conventional toddler bed, you might have to be careful when making the decision to use the crib mattress for the toddler’s bed.
Crib mattresses with waterproof coverings will most likely last longer. Mattresses that could be machine-washed are most likely to be reused for toddler beds. Since you don’t want your mattress to smell like urine or vomit once you transfer it to the toddler bed. Having the benefit of being able to wash it is a definite plus. If it seems that the crib mattress is winded in any manner or if it’s heavy-stained, do not use a mattress for a baby in your child’s bed.
Check it carefully for the mold, small black spots which may suggest bedbugs and tears on the cover, so that you may decide whether or not to use the mattress for your toddler’s bed. If you notice any of the issues, toss off the mattress and start with if you see any of them. If you’re a little doubtful, get your baby a new mattress. Don’t take chances! Your baby’s health is more important than saving a few bucks.